Browsing by Author "Wehr, JB"

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    Hydrolysis and dpeciation of Al bound to pectin and plant cell wall material and its reaction with the dye chrome Azurol S
    (American Chemical Society, 2010-05-12) Wehr, JB; Blamey, FPC; Hanna, JV; Kopittke, PM; Kerven, GL; Menzies, NW
    Hydrolysis of aluminum (Al) in solution increases at pH ≥ 4 and with an Al concentration. Pectin, an important anionic polysaccharide of plant cell walls, adsorbs Al, but this phenomenon is poorly understood. This study showed that Al3+ hydrolysis results in binding of Al to pectin in excess of the stoichiometric equivalent, leading to oversaturation of the pectin with Al. However, the degree of pectin methyl-esterification did not affect the extent of Al hydrolysis. Binding of Al to purified cell wall material also resulted in Al hydrolysis in a pH- and soluble Al concentration-dependent manner, but the source of cell wall material had no effect at fixed pH. Staining of Al-treated pectin and cell wall material from wheat (Triticum aestivum L.) and sunflower (Helianthus annuus L.) with the Al-specific dye, chrome azurol S (CAS), resulted in the formation of a purple color, with the intensity related to the extent of Al hydrolysis. © 2010, American Chemical Society